Echocardiography Quantification Of Z-scores In Normal Fetal Cardiac Dimensions

ObjectiveThe main goal was to develop z-scores reference ranges in normal fetal for common fetal echocardiographic measurements.MethodsA retrospective cross-sectional study of1232singleton fetals was performed for standard biometry biparietal diameter (BPD) and femoral diaphysis length (FL)) and an assessment of gestation age (GA)(no more than2weeks). Standardized fetal echocardiographic measurements included aortic valve annulus (AO), pulmonary valve annulus(PA),atrial septal length(ASL), foramen ovale diameter (FO) of the largest open amplitude at end-systole, End-diastolic measurements of the left ventricul (LV), right ventricul (RV) at the level of their respective atrioventricular valve annulus,and heart area(HA), thoracic area(TA) from a four-chamber view.Normal z-score ranges were developed for these echocardiographic measurements using GA, BPD and FL as independent variables.ResultsWe found a linear regression model between AO,PA,FO,ASL and three independent variables (FL,BPD, GA), A quardratic regression model between LV,RV,HA,TA and three independent variables.correlations between fetal cardiac measurements and the independent variables were excellent.There was significant heteroscedasticity of standard deviation (SD) with increasing independent variables, then using weighted regression of absolute residuals in order to minimize the effect of heteroscedasticity, developed regression models, there are linear regression models between SD of AO,PA,FO,ASL and quardratic regression models between SD of LV,RV,HA,TA and three independent variables.these equqtions allowing Z-scores to be calculated for fetal cardiac dimensions from knowledge of FL,BPD and GA.Conclusionsby applying statistical methods that are based on a large sample size development of reliable fetal z-scores for common fetal echocardiographic parameters. This permits exact assessment of growth of fetal cardiac structures in normal hearts and help improve clinical prenatal and perinatal management and timely intrauterine intervention.